The invention relates to a motor-pump unit, in particular for a high-pressure cleaning appliance, having an electric motor and a pump, the pump having a suction inlet for taking in liquid and a pressure outlet for discharging pressurized liquid, and the electric motor comprising a motor housing which is enclosed by a cooling housing, whereby a cavity is formed, it being possible for cooling liquid to be fed to the cavity via a cooling-housing inflow and to be conducted away therefrom via a cooling-housing outflow, and the cooling-housing outflow being in flow connection with the suction inlet.
Such motor-pump units are known from laid-open applications DE 35 45 665 A1 and DE 36 03 423 A1. They are used in particular in high-pressure cleaning appliances in which a liquid, preferably water, can be fed to a pumping chamber via the suction inlet, subjected to pressure and then discharged via the pressure outlet. The pump is driven by means of an electric motor. In order to cool the latter, a cooling liquid can be fed to the cavity between the motor housing and the cooling housing. In this context, DE 35 45 665 A1 proposes to cool the motor with water and to feed to the suction inlet the water which has been heated by the motor. This means that the pump can be used not just to subject liquid to pressure, but also to deliver the liquid through the cavity which encloses the motor housing. The motor-pump units which are known from DE 35 45 665 A1 and DE 36 03 423 A1 have a cup-like cooling housing with a cooling-housing inflow, which is disposed on the base of the cooling housing, and with a cooling-housing outflow, which projects radially from the cooling housing. In order to ensure a flow connection to the suction inlet from the cooling-housing inflow via the cavity and the cooling-housing outflow, it is therefore necessary to have costly connecting lines, for example hose lines, which require appropriate fittings to be fitted on the cooling-housing inflow and on the cooling-housing outflow.
It is an object of the present invention to develop a motor-pump unit of the type mentioned in the introduction such that, if required, a flow connection can easily be made from the cooling-housing inflow to the suction inlet via the cavity and the cooling-housing outflow.